What words should be used to kill children?!

What words should be used to kill children?! The Prophet (peace and blessings of Allah be upon him) used to seek refuge for Hasan and Hussain (may Allah be pleased with him) and said that your grandfather Ibrahim (peace be upon him) also used to seek Allah's refuge for Ismail and Ishaq (peace be upon him). I seek refuge in the words of Allah, the Almighty, from all the devils. And from all the eyes of the nation I seek refuge in the full words of Allah from every devil and every poisonous animal and every harmful evil eye. Sahih Bukhari: 3371]